1. Field of the Invention
This invention relates to detecting, measuring or recording bioelectric signals of the body. More particularly, this invention relates to generation of electroanatomic maps of the heart.
2. Description of the Related Art
The meanings of certain acronyms and abbreviations used herein are given in Table 1.
TABLE 1Acronyms and AbbreviationsLATLocal Activation TimeECGElectrocardiogram
Cardiac arrhythmias such as atrial fibrillation are an important cause of morbidity and death. Commonly assigned U.S. Pat. Nos. 5,546,951, and 6,690,963, both issued to Ben Haim; and PCT application WO 96/05768, all of which are incorporated herein by reference, disclose methods for sensing an electrical property of heart tissue, for example, local activation time, as a function of the precise location within the heart. Data are acquired with one or more catheters having electrical and location sensors in their distal tips, which are advanced into the heart. Methods of creating a map of the electrical activity of the heart based on these data are disclosed in commonly assigned U.S. Pat. Nos. 6,226,542, and 6,301,496, both issued to Reisfeld, which are incorporated herein by reference. As indicated in these patents, location and electrical activity is typically initially measured on about 10 to about 20 points on the interior surface of the heart. These data points are then generally sufficient to generate a preliminary reconstruction or map of the cardiac surface. The preliminary map is often combined with data taken at additional points in order to generate a more comprehensive map of the heart's electrical activity. Indeed, in clinical settings, it is not uncommon to accumulate data at 100 or more sites to generate a detailed, comprehensive map of heart chamber electrical activity. The generated detailed map may then serve as the basis for deciding on a therapeutic course of action, for example, tissue ablation, to alter the propagation of the heart's electrical activity and to restore normal heart rhythm.
Conventionally, a particular type of arrhythmia, characterized by the signal morphology of the arrhythmia, may be viewed on a single electroanatomic map generated from electroanatomical recordings. Other arrhythmias that are present in the electrical recording are often manually deleted. If the physician detects several morphologies, he may create a mixed map with polymorphic beats and separate them later on by moving points to a new opened map.